Sectional porous carrier forming a temporary impervious support

ABSTRACT

Compositions and designs are described for a sectional porous carrier used in processing microelectronics where thin device substrates are affixed by adhesive to the carrier and form an impervious bonded stack that is resistant to thermal and chemical products during processing and is easily handled by a substrate handling vacuum robot, and subsequently allows rapid removal (debonding) in batch operations by directional penetration into sectional porous regions by selective liquids which release the carrier from the device wafer without harm. The invention carrier with porous regions is used for temporary support of thin and fragile device substrates having capabilities of selective penetration of chemical liquids to pass through the porous regions, access and breakdown the bonding adhesive, and allow it to release without damage to the device substrate. The sectional porous nature of the carrier allows passive diffusion of chemical liquids, the manner which in contrast to mechanical, thermal, or radiative methods, is considered to be a higher yield practice and one which enables batch processing in a manufacturing environment utilizing practices of high throughput and low cost. Preferred designs include the use of porous metal forms, including laminates, as well as surface treatment of the porous regions to facilitate exclusion principles and achieve an inert support mechanism during the stages of device manufacture. These benefits allow design flexibility and low-cost batch processing when choosing practices to handle thinned device substrates in the manufacture of semiconductors and other microelectronic devices.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.62/010,800, filed Jun. 11, 2014 and is a divisional of U.S. applicationSer. No. 14/737,184 filed Jun. 11, 2015

FIELD OF THE INVENTION

The present invention relates generally to the temporary support ofthinned substrates in preparation for manufacturing microelectronicdevices. Specifically, the invention describes a carrier substrate witha porosity and surface chemistry to selectively allow fluids topenetrate and come into direct contact with the adhesive used to bondonto the device substrate. More specifically, the carrier exhibitssimilar properties as silicon, glass, or another ceramic, yet hasporosity in regions or sections (“sectional porous carrier”) to allowthe penetration of liquid chemistry to selected regions or sections toeffect directional penetration of the given liquid to contact theadhesive at such specific areas and effect its breakdown, degradation,and otherwise dissolution leading to debonding (release) of the carrierwithout harm to the device substrate. The porous regions or sections ofthe carrier includes solid geometric areas as laminated structures. Theporous regions or sections of the carrier also includes surfacetreatment that facilitates exclusion of chemicals during processing, yetallows passage of selective liquid chemicals used to effect debondingand release. In a preferred embodiment, the carrier release occurs whileleaving the electronic device substrate without harm affixed to a tapedfilm frame. In particular, the liquid chemistry may be prepared andheated in a tank of sufficient size that accepts a cassette or similarfixture that holds multiple sectional porous carrier bonded stacks in animmersion batch process allowing the simultaneous debonding and releaseof multiple sectional porous carriers. Operations conducted on multipleunits per time interval (“batch processing”) are consistent with theobjectives of high volume manufacturing leading to increased throughputwhile reducing costs. Device substrates include semiconductors,microelectromechanical systems (MEMS), solar, flexible displays, andother thin solid materials that must be temporarily supported duringtheir manufacture.

BACKGROUND OF THE INVENTION

Electronic devices face continued pressure to design and produce theirconfigurations to a further state of miniaturization, ergonomicallypleasing shapes, and a reduced weight. To achieve these goals,substrates must be thinned to 100 um (microns) and less, making themextremely fragile and difficult to handle with existing equipment. Toprevent breakage, cracking, or otherwise chipping and stressing thesefragile substrates, it becomes necessary to always keep them temporarilysupported by an external platform, being a rigid carrier or a membrane.During microelectronic manufacturing, the thinned substrates aretemporarily supported by rigid carriers, as these provide the mostsecure and reliable media to conduct high-resolution processes. Thesecarrier substrates may be composed of sapphire, quartz, certain glasses,or silicon and exist in thicknesses from 0.5-1.5 mm(millimeters=500-1,500 um). The device substrate is commonly affixed tothe carrier by an adhesive that offers sufficient adhesive force andquality to withstand the manufacturing process, while also allowing thethinned substrate to be removed at the completion of work without damageto its integrity.

Common tape adhesives exist which offer temporary support to the devicesubstrate either alone or used as an interface to the carrier. Thesematerials are commonly used for dicing operations, including high-volumephotodegradative delamination practices (i.e. pick-and-place). However,tape adhesives are reserved only for the end of the process where dicingoccurs. Most tape adhesives are not used in upstream microelectronicprocesses as their properties do not meet the needs for fabrication,including rigidity and uniformity, thermal and chemical resistance, andoutgassing (weight loss). These shortcomings in adhesive tapes result inloss of adhesion, gas bubbles lodged in-between the device substrate andcarrier, or produce unwanted gaseous by-products of degradation thatadversely interact with the processes of vacuum deposition or etching toproduce inferior results.

In the example where thinned substrates include semiconductor wafers,the device substrate is commonly removed from a carrier support,cleaned, and mounted to a film frame containing tape adhesive, allowingthe dicing process to proceed. Carrier removal is conducted with roboticassisted complex tooling. Tooling is designed according to the type ofadhesive chosen. At the time of this invention, there are no less thansix (6) adhesive materials on the market. The majority of theseadhesives require a single wafer tooling configuration whereby the toolhandles one wafer at a time.

In semiconductor operations, single wafer processes that usethermoplastic adhesives may utilize thermo-mechanical demounting astaught by Thallner in U.S. Pat. No. 6,792,991 B2 (2004) and 2007/0155129(2007). Device wafer separation is achieved by heating the mounted stackto a temperature above the melting point of the thermoplastic adhesivewhile simultaneously applying a shear force in a manner designed toseparate the mounted surfaces. Cleaning with a selected organic solventtypically follows to ensure residual adhesive is cleaned from thesubstrate.

Another single-wafer tooling practice for removing carrier supports isdescribed in U.S. Patent Application Nos. 2009/0017248 A1 (2009), Larsonet al., 2009/0017323 A1 (2009), Webb et al., and in the InternationalApplication WO 2008/008931 A1 (2008), Webb et al. The adhesive describedis a bilayer system composed of a photothermal conversion layer and acurable acrylate. The applications cite the use of a laser irradiationdevice which allows rapid demount of the external support carrier and isfollowed by a mechanical peeling practice of the curable acrylate fromthe thinned substrate.

Laser ablative carrier demounting practices are demonstrated inmicroelectronics manufacturing as described in U.S. Pat. No. 6,036,809(2000) Kelly, et. al, U.S. Pat. No. 7,867,876B2 (2011) and U.S. Pat. No.7,932,614B2 (2011) Codding, et. al. Laser ablative tooling isnon-trivial, in that it requires exacting focus of an optical device ofa specific wavelength and to do this onto an interface between the workunit and the carrier substrate. The laser's focus does this while it orthe substrate is being shifted in continual motion moving rapidly acrossthe substrate. It is well known to those familiar with the art ofcoatings and planarization efforts that irregularities will exist inmaterials applied over the surface of the work unit. The adhesives usedfor these practices vary between rubber, silicone, polyimide, acrylic,and the like. The laser transmits through an optically clear carriersubstrate and focuses onto the interfacial region where the adhesivemeets the carrier, causing a significant and immediate rise intemperature which burns the material and destroys the adhesive interfaceto the carrier. The laser continues rastering to the next location in anapparent smooth fashion until the entire surface of the substrate hasbeen exposed and thereupon the carrier release is expected. The impactsof this process is realized later when irregularities are observed asmicro-cracks, fissures, and residue that is burnt onto surfaces whichcannot be removed. Laser ablative processes, although a common practicefor debonding delicate substrates, remains a subject of much discussionwhen considered for high volume manufacturing.

These and other carrier debonding (removal) practices are discussed inU.S. Patent Application No. 2009/0218560A1 (2009) Flaim, et. al, wherethe author consolidates the practice of wafer and carrier separationinto four approaches, including: 1) chemical, 2) photodecomposition(laser ablation), 3) thermomechanical, and 4) thermal decomposition.Although the author mentions drawbacks in each mechanism, they refrainfrom classifying them as single-wafer or batch processing according totheir respective tooling configuration. Of these four processes, onlychemical penetration is considered as a batch mechanism. In suchprocesses, wafers may be populated into a cassette or holder andimmersed into a chemical liquid for a designated time to allowpenetration into the adhesive, emulsification, and removal to allowcarrier debonding. Chemical diffusion-based debonding may requireseveral hours to complete. At the time of this document writing, commonthroughput for single wafer processes are scheduled for 20-25 wafers perhour (wph). In the case of a conventional chemical debond whereperforated (drilled holes) carriers are used, cassettes of between 12-25wafers are used where debonding may last up to four (4) hours. For abath size of >100 liters as common for most fabrication facilities inAsia, this volume can accommodate up to 4 cassettes at a time, providingthroughputs between 12-25 wph, exceeding that for single wafer processes(i.e. 12-25 wafers per cassette×4 cassettes=48-100 wafers/4 hrs=12-25wph). Without being bound to variations of the art of batch processing,this option is needed in fabrication to offer lower cost options fordebonding carrier substrates. Therefore, it is a desire to consideroptions that enable batch wafer processing as a viable and costeffective practice for thin substrate debonding from carriers.

Other semiconductor batch debonding processes are described in U.S. Pat.No. 6,076,585 (2000) Klingbeil, et. al, and U.S. Pat. No. 6,491,083 B2(2002) De, et. al, where a fixture holding thinned gallium arsenide(GaAs) wafers are removed from sapphire carriers using an immersionchemical practice. In both of these inventions, the fixture is designedto operate with the wafers held horizontally. The fixture has stepsmachined within it and requires a perforated carrier substrate that isslightly larger in diameter than the device wafer, such that during thedebonding operation, the separation of the two substrates occurs by oneitem landing upon the fixture step while the wafer separates and fallsto a lower level of support. Carrier substrates that are machined to belarger in diameter than the work unit and which have perforations(drilled holes) can be costly. For example, enlarged perforated sapphiresubstrates are a common choice for GaAs work unit wafers, however, thesecan cost $1,000 or more per unit. In the case of silicon substrates ofdiameters at 12″ or the projected 18″ (at the time of this writing,plans are projected), carrier wafers are chosen to be dummy type (i.e.same size, shape, and composition of the work unit without theelectronic purity). Oversized perforated carriers are cost prohibitivefor large diameter silicon as the cost of machining holes (perforations)can fall between factors of 10-100× the cost of conventional dummy sizedwafers. It is a desire to avoid the use of oversized perforated carriersas a means to minimize process costs.

Semiconductor batch demounting processes are also described in U.S. Pat.No. 6,601,592 B1 (2003) and U.S. Pat. No. 6,752,160 (2004) ZhengmingChen, where two fixture cassettes work in conjunction with each other ina manner that allows separation of the device wafer from carriersubstrates. The inventions describe the batch process separation betweendevice wafer and carrier as conducted such that the top fixture cassetteis populated with the mounted wafers whereby during liquid immersion,the chemistry penetrates the adhesive contact to release the twosubstrates. The top fixture cassette is constructed in a manner to allowonly the device wafer pass downwards to the lower fixture cassetteduring gravity assisted separation, retaining the carrier substrate. Theinventions require the sized of the carrier substrate and device waferto be different, either the device wafer to exhibit a flat edge (i.e.wafer flat) or the carrier substrate to be oversized as compared to thedevice wafer. In either case, when the process commences and the fixturecassettes are arranged vertically, the oversize carrier is held backwithin the above fixture cassette while the device wafer travels fromthe top to the bottom cassette. Device wafers with a flat location wereat one-time popular for reasons of reference location when handling andtransferring from one process to another. The wafer flat is lessdesirable as it eliminates valuable device manufacturing realty on thewafer and reduces the number of devices built upon a substrate.Conversely, oversized carrier wafers are cost prohibitive as describedearlier in this document. Further and most important, these inventionsdescribe fixture design that requires the device wafer to be separatedand released from the carrier substrate and move freely from one fixturecassette to another during liquid chemical immersion processing. It iscommonly understood in the practice of thin wafer handling, that atanytime during this work, the device wafer should always be supportedand never left to move freely. Consistent device wafer support wouldminimize irregular bending, vibration, and edge contact that wouldgenerate cracks, chipping, and other flaws within a thin wafer. It is adesire to avoid fixtures that require device wafer flat designs oroversized carriers and to avoid fixtures that promote a batch processingpractice which allows the device wafer to move freely and subject itselfto cracks, flaws, or other signs of breakage.

A unique semiconductor carrier formation and process for separation fromthe device wafer is described in the International Publication No. WO210/107851 A2 (International Application No. PCT/US210/027560), Moore,et al, where a carrier substrate is manufactured (formed) directly ontothe device wafer in a manner sufficient to support grinding and backsideprocessing and when complete, the materials used to form the carrier aredesigned to break down in a liquid chemistry cleaning process. Carrierdigestion during a cleans process requires a special fixture to supportthe device wafer without damage and the simultaneous multiple processingof such items during a batch operation. Once the carrier is digested andremoved, the device wafer is anticipated to exhibit some level ofmobility within the special fixture. The movement of a thin fragilesubstrate within a mechanical fixture is anticipated to produce cracks,fissures, and other irregularities due to vibration and movement of theliquid. It is a desire to promote a batch process which mandates supportof the device wafer during carrier debonding.

The use of porous carriers in processing a work piece is described inU.S. Pat. No. 7,708,854 B2 (2010) Kroninger et al., where the authordiscusses the affixing (bonding) the carrier to the work piece andgrinding or polishing to desired level followed by chemical diffusionthrough the porous carrier with chemicals to effect release andseparation of the work piece. The claims describe the practice yetsuffers from several fundamental aspects that are important formainstream microelectronics processing. The first aspect is the claim bythe author to apply liquid adhesive to the carrier. While the lay readermay not find this to be of critical concern, it should be understoodthat the majority of microelectronic processing where thin handling isrequired by a carrier support, the adhesive is always applied to thedevice substrate. Applying liquid adhesive to the device substrateallows coverage and curing over topography. The protection of thetopography by planarizing or flattening this zone will reduce theoccurrence of bubbles or voids in and around the topography. Second, theuse of vacuum assisted adhesive coating and penetration will result inreduced performance during debond and become a source of contamination.Adhesive is applied as a liquid to the porous carrier and begins topenetrate and fill the pores. Vacuum is applied which pulls the adhesivefurther into the pores deep inside the carrier. This practiceeffectively forms a solid composite structure comprising the adhesiveand porous carrier. This solid structure discourages effect of chemicalfluids on the adhesive and stops the passage of fluid through the porouscarrier. Chemical action on the adhesive within the porous carrieractually dissolves slower as compared to a pure solid of adhesive (bulkform of same dimensions). This is due to the fundamental model ofplastics and polymers when in exposed to solvent liquids. According tothe model, there is a series of steps in dissolvingadhesive/polymer/plastic. The steps include: exposure, absorption,swelling, saturation, break-up and passage to bulk fluid, and finally,further reduction in the bulk fluid. Adhesive that is present in theporous carrier begins to absorb solvent, it swells, increase its volume,however, the porous structure limits continued volume expansion.Therefore, the adhesive present in the porous carrier is slow to reachsaturation and in turn will even be slower to break-up and enter thebulk solvent. Adhesive present in the pores of the carrier will remainmuch longer as compared to a pure form bulk adhesive specimen. Third,the author describes the porous carrier to be open (porous, permeable)after bonding (i.e. bonded to work piece). The bottom of the porouscarrier is open, not sealed. This condition is not satisfactory formicroelectronic processing. Open or porous carriers require excessivepump-down times during vacuum assisted plasma processes. Further, openor porous substrates allow chemical intrusion and become impossible toeffectively clean prior to the next process step. In this condition, theporous carrier becomes a serious source of contamination in thefabrication area causing yield reduction and high scrap rates. There isa need for a porous carrier whereby adhesive is not applied directly toits structure, is not vacuum assisted to force adhesive into its pores,and is completely closed (impervious to chemicals) such that the bondedstack will support microelectronic fabrication (backside processing).

There exist compelling arguments to encourage batch process designs withspecially designed porous carriers that avoid the high cost ofperforated carriers, discourage costly and complex fixtures, controlprotection and safety to device substrates, and ensures continualsupport of the device substrate throughout the process. For thesereasons and others not mentioned, it is a desire to create a carrierthat supports a device substrate during fabrication high volumemanufacturing using vacuum assisted handling tools and is able to beexposed to thermal and chemicals and that also debonds rapidly withoutharm to the device substrate and supports multiple unit operations in abatch process for high throughput and low-cost benefits.

SUMMARY OF THE INVENTION

This invention is directed to a sectional porous carrier design andcomposition used as a temporary support for handling thin and fragiledevice substrates in microelectronic operations and enables asimultaneous method of demounting (separating) them from the devicesubstrates in a rapid and efficient manner without damaging the devicesubstrates. When bonding a sectional porous carrier, an adhesive isapplied to the device wafer and then brought into contact with thecarrier. The result is an impervious bonded stack containing thesectional porous carrier used as temporary rigid support and the devicesubstrate. A sectional porous carrier exhibits regions or sections ofits structure such that at least one geometric side is solid(non-porous, impermeable). The structure offers porosity within sectionsor zones to allow directional fluid penetration to facilitate controlleddebonding. For purposes of substrate debonding, porosity is defined asthe extent of wicking or chemical diffusion sufficient to saturate thedesired region of the carrier where bonding (affixing) occurs with thedevice substrate. Example designs of a sectional porous carrierconstructed with porous materials in a laminated structure that exhibitsminimum porosity and sufficient surface finish necessary to be used as atemporary support for electronic devices (FIG. 1). FIG. 1 Illustratesdesign options A-E for the sectional porous carrier, each comprising aregion or section that is porous (#1) and that which is a solid (#2,non-porous, impermeable). For simplicity and clarity of illustration,the drawings are not necessarily drawn to scale.

Sectional porous carrier A comprises a porous material #1 laminated to arigid solid (non-porous) structure #2. The materials are bonded by alaminating and welding or fusion practice deemed sufficient to maintainthe structure's sectional porous property. The porous carrier comprisesa material #1 that may be present at 1% or more by weight and laminatedonto solid structure #2 that represents the remaining percentage balance(i.e. 99% or less). Porous material #1 exhibits a sufficient surfaceuniformity represented as the total thickness variation (TTV) of themeasurements, having values of 10 um (microns) or less. The otherexample designs shown as B-E follow similar design descriptions as thatdescribed for A of the porous material #1 and solid material #2.

A variety of materials may be used in this invention as inorganic andcomposite structures that comprise both inorganic and organic species.Inorganic materials include metals, ceramics, and salts. Metals may beused in the invention in a variety of forms to produce porous or solidmaterials, including copper (Cu), nickel (Ni), iron (Fe), cobalt (Co),titanium (Ti), tantalum (Ta), tungsten (W), molybdenum (Mo), chromium(Cr), aluminum (Al), gold (Au), silver (Ag), neodymium (Ne), palladium(Pd), platinum (Pt), osmium (Os), iridinium (Ir), rhodium (Rh),ruthenium (Ru), nitrides thereof, such as titanium nitride (TiN, orTiN_(x)), where x represents the stoichiometry of the thermodynamicallystable material, and silicon nitride (Si₃N₄), and alloys thereof, suchas nickel iron (NiFe) as in the alloy trade name as Invar (Ni₄₀Fe₆₀),stainless steel containing chromium, nickel, iron, and other alloyedelements in forms of stainless steel represented as austenitic,ferritic, and martensitic, sufficient to meet the needs of the finalstructure. The metal composition may exhibit properties of corrosionresistance, low coefficient of thermal expansion (CTE), and rigidity ashigh modulus.

Ceramics may exist in the invention as solid form materials, varying inporosity, and existing in the invention as crystalline and amorphouscomposition. Such examples of ceramics include silicon, galliumarsenide, quartz, glass, sapphire, and alloying mixtures thereof. Theseceramic and glass materials exist initially as solid structures in theform of sheets, panels, disks, or other form substrates in a designwhich meets the objective form of the invention. Porous ceramicsoriginate as powders and fibers that are sintered (bonded) into formsthat result in structures exhibiting a high degree of porosity.

Sectional porous carriers may be constructed from inorganic materials asvarious alkali element or related conjugated salts present in a carriersolvent (e.g. water, etc.). Such conjugated salts may exist in an ionicmixture where cations may include ammonium (NH₄ ⁻), hydronium (H₃O⁺) andmetals as M^(+n), where M includes Al, Sb, As, Ba, Be, Bi, Cd, Ca, Cr,Co, Cu, Fe, Pb, Li, Mg, Mn, Hg, Ni, K, Sc, Ag, Na, Sr, Sn, and Zn, and nvaries from 1 to 5. Anions present in the inorganic mixture may bepresent as acetates, borates, bromates, carbonates, chlorates,chlorites, chromates, cyanamides, cyanide, dichromates, ferricyanide,ferrocyanide, phosphates, sulfates, nitrate, sulfite, oxide, oxalate,nitride, nitrite, hydroxide, hypochlorite, permanganate, silicate,stannate, stannite, tartrate, thiocyanate, and halogens as Y^(−x), whereY is Br, Cl, F, H, I, O, N, P, and S, and x varies from 1-3. The cationsand anions exist as conjugates of each other, as in the case of KCl(i.e. K⁺/Cl⁻).

Organic materials may also be incorporated into the invention design assolids, fillers, or binders, including polyimides such as Kapton®(registered trade mark of E.I. du Pont de Nemours and Company),polyarylether such as Arylite® (registered trade mark of Ferrania),polyesters such as Mylar® (registered trade mark of DuPont TeijinFilms), polypropylene, polyethylene, polysulfone (polysulfone,polyethersulfone, polyphenylsulfone) such as Radel® (registered trademark of Solvay Solexis), polybenzimidazole, polyphenylene sulfide suchas Torelina® (registered trade mark of Toray Film Products, Co., Ltd.),polycarbonate, polystyrene, polyacrylic, fluoropolymers asfluoroethylene propylene (FEP), perfluoroalkoxy polymer (PFA),ethyltetrafluoroethylene (ETFE), and ethylene-chlorotrifluoroethylene(ECTE) such as Halar® (registered trade mark of Solvay Solexis),polyvinylidene fluoride (PVDF) such as Kynar® (registered trade mark ofSolvay Solexis), polyether ether ketone (PEEK), polyether imide (PEI),polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), andvarious polyamides classified as nylon. Organic polymers may exist asfilms or particles, be cast from solutions, or produced from otherpathways such as thermo-mechanical forming.

Where a sectional porous carrier comprises an organic material in theform of a film or particle to produce a laminate or composite, it isgenerally understood that such chemistries may originate from differentfamilies that will define the final properties of the carrier substrate.Many of these organic polymers are reactive materials that undergocrosslinking to produce a thermoset. Those familiar with the artrecognize that in order to effect the reaction of such chemistries,there must also include the necessary initiators. These initiators areconsidered as cross-linkers, activators, catalysts, or reactors, andrepresent a small portion of the overall composition. Therefore, itshall be understood that whenever mention is made about the use of aspecific polymer or resin, that material may also include the respectiveinitiator, and the choice of the initiator may produce certain subtledifferences, the primary emphasis is that an initiator that is matchedwith the chemistry of choice must be included in the system.

The sectional porous carrier that is constructed of organic materialsmay comprise a variety of base resins. The reactive resins include, butare not limited to, those undergoing cross-linking polymerizationmechanisms, including epoxies, acrylates and silicones. These systemsundergo thermal, chemical, and photo-initiated polymerization bycondensation and addition mechanisms as described in the literature asthermosets. Thermoset chemistries offer rigidity and resistance to theprocess conditions. Non cross-linking resins include those described asamorphous or thermoplastics. The thermoplastic resins may add strengthand durability to the adhesive. Additional properties by amorphouspolymers include barrier (gas non-diffusion), temperature resistance,transparency, detergency, and water solubility. The following passagesoffer more detail on the resins used in the construction of a porouscarrier, but is not limited to the resins identified here.

Epoxy resins used for this invention may comprise a single or multipleepoxide functional group, also called oxirane, or ethoxyline, normallyidentified as a three-membered oxide ring described by the followingstructures classified as (1) glycidyl ethers, (2) glycidyl esters, (3)gylcidyl amines, (4) linear aliphatics, and (5) cycloaliphatics:

where both R, R¹, and R² may represent the following: hydrogen (—H),amide (—NH₂), methyl (—CH₃), hydroxyl (—OH), alcohol (—CH₂OH), or anyone of the groups represented by the formula —C_(n)H_((2n)),—C_(n)H_((2n+1)), or —C_(n)H_((2n))OH where n varies from 2-20; cyclicand aromatic hydrocarbon functional groups of the formula —C₆X₅, where Xmay be substituent groups such as hydrogen (—H), the halogens (—F, —Br,—Cl, —I), hydroxyl (—OH), and —COOH groups, R³ represents a cyclic oraromatic structure of the formula —C₆X₅, where X may be substituentgroups such as hydrogen (—H), the halogens (—F, —Br, —Cl, —I), hydroxyl(—OH), and —COOH groups, all of these variations may exist in multiplesubstituent formats, or monomers, as given in the example structure (6):

wherein structure (6) describes a polymer comprising monomers ofglycidyl ether with substituent R and linked by R¹. Such resins mayinclude: CARDOLITE 514 (difunctional glycidyl ether epoxy resin)produced by Cardolite Corporation, ADEKA EP 4088S (epoxy resin andurethane resin curing agent) produced by Adeka Corporation, EBECRYL3605(partially acrylated bisphenol-A epoxy) produced by Cytec Industries,Inc.

In one embodiment, the epoxy resin includes that of structure (6),wherein the monomeric epoxide substituent is of the novolac variety,also referred to as epoxidized novolac resin, where R represents anaromatic ring of the form C₆X₅, where X may be substituent groups suchas hydrogen (—H), the halogens (—F, —Br, —Cl, —I), hydroxyl (—OH), and—COOH groups, and the linkage R¹ is best represented by substituents ofthe formula —C_(n)H_((2n)). Such epoxy novolac resins include 3-6epoxide groups per molecule (n=1.6) of the general formula exhibited bythe structure (6). General commercialized products which meet thiscriteria include: DEN 431 and DEN 439 produced by The DOW ChemicalCompany; EPON 154, EPON 160 and EPON 161 produced by ResolutionPerformance Products (Hexion), REZICURE 3056 produced by SI Group.

Acrylic monomers and polymers used in this invention include acrylateesters by the general formula described in item (7), where both R₁ andR₂ may represent the following: hydrogen (—H), amide (—NH₂), methyl(—CH₃), hydroxyl (—OH), alcohol (—CH2OH), or any one of the groupsrepresented by the formula —C_(n)H_((2n+1)) or —C_(n)H_((2n))OH where nvaries from 2-20; aromatic hydrocarbon functional groups of the formula—C₆X₅, where X may be substituent groups such as hydrogen (—H), thehalogens (—F, —Br, —Cl, —I), hydroxyl (—OH), —COOH; and —COOR₃ groups,wherein R₃ represents the following: hydrogen (—H), amide (—NH₂), methyl(—CH₃), hydroxyl (—OH), alcohol (—CH2OH), or any one of the groupsrepresented by the formula —C_(n)H_((2n+1)) or —C_(n)H_((2n))OH where nvaries from 2-20.

It is to be understood that where substituent groups are present, theyshould be present in a manner such that they do not unduly hinder orinterfere with the thermal or photo initiated cure of the acrylicmonomer. The preferred acrylic monomers are those represented by item(7), wherein R₁ is a hydrogen (—H), or methyl (—CH₃), defining themolecule as an acrylate or methacrylate, respectively, and R₂ torepresent a substituent of the form or —C_(n)H_((2n))OH where n variesfrom 2-20. Such preferred acrylics include hydroxyethyl acrylate (CAS#818-61-1), hydroxypropyl acrylate (CAS #25584-83-2), hydroxyethylmethacrylate (CAS #868-77-9), and hydroxy propyl methacrylate (CAS#27813-02-1). The more preferred acrylic monomers are those representedby item (7), wherein R₁ is a hydrogen (—H), or methyl (—CH₃), and R₂ torepresent a substituent of the form amide (—NH₂), defining the moleculeas an acrylamide. Such preferred acrylics include n,n-dimethylacrylamide(DMAA, CAS #2680-03-7). DMAA has been shown to exhibit highcompatibility and solubility for other resins and a significantly fastercuring time over the conventional acrylates or methacrylates.

Polysiloxane resins suitable for use herein exist in commerce bymultiple suppliers, exhibiting broad classification differences insilicone subcategories, types, and polarities, and reacting throughdifferent mechanisms, including addition and condensationpolymerization. The use of such materials in the preparation of theadhesive shall consider compatibility and reactivity between thepolysiloxanes as a key factor in determining their final behavior. Forexample, species of similar polarity may be compatible yet beinconsistent in their preferred reaction mechanisms. These includeorganofunctional polysiloxanes and silicone resin intermediates, bothare expected to undergo thermal initiated condensation reactionsfollowing hydrolysis. However, vinyl silicones (rubbers) are largely aphobic chemistry and undergo addition reactions with metal catalysts.Therefore, we will differentiate these chemistries accordingly, as theiruse in an adhesive is expected to follow the same considerations ofcompatibility and reactivity.

The preferred polysiloxanes include oxysilanes of the formulasrepresented as (R₁)—[(R₂)(R₃)SiO]_(n)—R₄ or (R₅)O—[(R₃)₂SiO]_(m)—R₅,where R₁, R₂, and R₃, may exist as a hydrogen or carbon containingfunctional group of the variety as alkyl, phenyl, cycloalkyl, alkoxy,hydroxyalkyl, alkoxyalkyl, and hydroxyalkyalkoxy, where these groups maycontain up to 6 carbons, and R₄ comprises hydrogen, alkyl, or phenyl,where a minimum of 2 of the groups are oxy substituents used forpolymerization, and R₅ is similar to R₄, however, there may exist up to12 carbons, and n and m varies from 1-5 or to a sufficient number toreach a molecular weight of 500,000.

Siloxane resins suitable for use herein include a broad range of alkyl,aryl, oxygenated, and cyclic substitutions. In the case where thermalresistance is critical, the substitution will be methyl and phenyl. Themoieties on the siloxane can also exhibit specific organic functionalgroups that are well known to interact with the chemistry of thesubstrate interface. For example, in the case of a mercaptan siloxanemoiety, the sulfur group interacts with certain inorganic solidsurfaces, such as metals, to increase the interfacial adhesion force.Most importantly, moieties which exhibit epoxy, acrylic, or aminecharacter, are known to interact with a corresponding chemistry withinan organic matrix and at the interface of polymeric solid surfaces,resulting in molecular entanglement and van der Waals interactions ashydrogen and covalent bonding, factors which improve the condensationcharacter and density of the structure and believed to improve surfacefinish.

Silicone resins based on cyclic siloxane molecules are preferred. Usefulcyclic silicones are hydroxy functional cyclic silicones classified asliquid resins, flake resins, and silicone intermediates as provided bysuppliers Dow Corning and Wacker Silicones (Wacker-Chemie GmbH).Preferred cyclic siloxane choices for adhesive development, includethose with high compatibility with other polymers, dissolution in a widerange of solvents, and those classified as silanols. These silanolcompounds exhibit relatively high capacity for condensation reactivityand include those with two or more hydroxyl groups per cyclic siliconemolecular unit and a phenyl/methyl ratio ranging from 50-120% and amolecular weight ranging from 4,000 to 300,000. In all cases, therelative content of silicon dioxide is high, usually greater than 50%.

The choice of initiator is dependent upon the polymer and theapplication. Epoxy based systems use organic amine and acid materials toopen the oxirane ring and initiate cross-linking. These may be promotedby thermal or photo means. Free-radical initiators are used withacrylics, also promoted by applications that apply heat or ultravioletexposure. Silicone vinyl compounds require metal catalysts to initiatefree-radical generation. These classes of initiators and the requiredmedia to support polymerization and enable applications of the adhesiveto facilitate fixation of the two surfaces. In one embodiment, an epoxyresin system is used with an initiator which is of the polyamine formand of higher molecular weight. Higher molecular weight aminechemistries will remain in the system for longer durations and providean environment, which efficiently cross-links the epoxy resin. Aminesmay include triethylenetetramine (TETA), N-methylethanolamine (NMEA),and N-methyldiethanolamine (DMEA) produced by The DOW Chemical Company,and meta-xylenediamine (MXDA) as produced by Mitsubishi ChemicalCompany. Desirable amine amounts are typically present at levels fromabout 1% to about 5%, by weight as compared that of the epoxy. A similarapproach for epoxies may also be used with acidic materials. The acidstend to have higher reaction rates with epoxies over that of amines.Preferred acids are various sulfonic acids such as toluene,dodecylbenzene, and methane sulfonic acids. The epoxy begins to reactupon contact, so the means of mixing and application must be considered.Where acidic reactions are preferred for epoxies are in the case ofphoto acid generators (PAGs). These systems comprise sulfonium saltswhich release varying molecular weights of toluene sulfonic acid tocause immediate reaction. This rapid reaction is used in manyphotoresists. One common photoacid generator is triphenylsulfoniumtrifluoromethane sulfonate (TPST). Typical amounts of a PAG is in therange of <2% by weight of epoxy.

Initiators for acrylic monomers include thermal (thermal radicalinitiator, TRI) or photo activated free radical initiators. It is wellknown from the literature that these free-radical initiated systems willcombine with the vinyl group of the acrylic, initiate a chain reaction,whereby the product acrylate free radical combines with other vinylgroups of adjacent acrylics and produce final crosslinked product. TheseTRI materials include inorganic persulfates such as ammonium persulfate(APS), potassium persulfate, and sodium persulfate, and organicpersulfates such as quaternary ammonium persulfates (e.g. tridodecylammonium persulfate); peroxides include benzoyl peroxide (BPO), methylethyl ketone peroxide, dicumyl peroxide, and benzopinacole (BK), cumenedihydrogen peroxide, and those organic peroxides under the tradenameLuperox™ (Arkema, Inc., www.arkema-inc.com), azo-compounds including2,2′-azobisisobutyrnitrile (AIBN), 4,4-azobis(4-cyanovaleric acid),1,1′-azobis(cyclohexanecarbonitrile), acetates as peracetic acid, andtert-butyl peracetate. Benzoin photoinitiators are common for use asinitiators for acrylic chemistry. One type of benzoin photosensitizer is2-phenylacetophenone, which undergoes photoscission to release radicalsof benzoyl, and benzyl, which become the primary chain polymerizationinitiators in the curing process. Photochemically generated freeradicals react directly with the double bond of the vinyl monomer as achain-initiating step. The invention involves a cure process between aphotoinitiator that is present in the liquid polymer system and actinicradiation from an ultraviolet emission source. Common photoinitiatorsinclude benzoin ethers, acetophenones, benzoyl oximes, andacylphosphines. These initiators may include phenylglyoxylate,benzyldimethylketal, oaminoketone, ohydroxyketone, monoacyl phosphine(MAPO), bisacylphosphine (BAPO), metallocene, and iodonium salt.Preferred initiators include 2-hydroxy-2-methyl-1-phenyl-1-propanone(CAS #7473-98-5) and phosphine oxidephenylbis(2,4,6-trimethylbenzoyl)—(CAS #162881-26-7). A trade nameproduct, which represents these materials, includes Irgacure 2022, asmanufactured by CIBA Specialty Chemicals, Basel, Switzerland. Theproduct exhibits absorption maxima at 365 nm, 285 nm, and 240 nm.Concentrations are used anywhere at ≤5% by weight.

Organic polymer mixtures that comprise silicone resins may containanywhere from 20-100% solids of polymers having polysiloxane-vinyl andsilyl-hydride character. In the presence of a metal catalyst, the vinylcompounds initiate free radicals that undergo addition polymerizationwith the silyl-hydride to produce a polymerized final product. Tocontrol the reaction rate for application and bonding, there arechelates binding the platinum. During heat exposure, the chelatedegrades to release platinum and then triggers polymerization. In thecase of silanol polysiloxanes, these monomers will crosslink upon heatexposure, usually in the range 200-250° C.

Additives may be used to improve specific properties in constructing aporous carrier. For example, the use of fluoropolymers are known forsurface sensitive activity. The addition of fluoropolymer surfactantsmeet this objective. Other common surfactants as nonionics or chargedspecies as cationic or anionic are known to provide surface sensitiveadjustments to produce a desired surface energy that is conducive to itsuse. Additives may also contain fillers. These are specificallyexemplified by fibrous fillers to improve regional mechanical strength.Particles may also be used to improve mechanical strength and are usedto effect porosity. Such materials include glass fiber, asbestos,alumina fiber, ceramic fiber composed of both alumina and silica, boronfiber, zirconia fiber, silicon carbide fiber, metal fibers, polyesterfibers, aramid fiber, nylon fibers, phenolic fibers, natural plant andanimal fibers; granular or particulate fillers such as fused silica,precipitated silica, fumed silica, calcined silica, zinc oxide, calcinedclay, carbon black, glass beads, alumina, talc, calcium carbonate, clay,aluminum hydroxide, barium sulfate, titanium dioxide, aluminum nitride,silicon carbide, magnesium oxide, beryllium oxide, kaolin, mica,zirconia, and so forth; and mixtures of two or more of the preceding.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 represents example designs of a sectional porous carrierconstructed with porous materials in a laminated structure that exhibitsminimum porosity and sufficient surface finish necessary to be used as atemporary support for electronic devices. FIG. 1 illustrates designoptions A-E for the sectional porous carrier, each comprising a regionor section that is porous (#1) and that which is a solid (#2,non-porous, impermeable). For simplicity and clarity of illustration,the drawings are not necessarily drawn to scale. Sectional porouscarrier A comprises a porous material #1 laminated to a rigid solid(non-porous) structure #2. Sectional porous carrier B illustrates aporous material inset into the rigid solid, where sectional porous Cillustrates a porous material that is smaller than the dimensions of therigid solid. The materials are bonded by a laminating and welding orfusion practice deemed sufficient to maintain to structure's sectionalporous property. The porous carrier comprises a material #1 that may bepresent at 1% or more by weight and laminated onto solid structure #2that represents the remaining percentage balance (i.e. 99% or less).Porous material #1 exhibits a sufficient surface uniformity representedas the total thickness variation (TTV) of the measurements, havingvalues of 10 μm (microns) or less. The other example designs shown asD-E follow similar design descriptions as that for A-C of the porousmaterial #1 and solid material #2. Sectional porous carrier Dillustrates a variation of porosity at the center of the porousmaterial, while sectional porous carrier E has a crossed structure inthe porous material design.

DETAILED DESCRIPTION OF THE INVENTION

The following describes in detail one embodiment of the invention andseveral variations of that embodiment. This discussion should not beconstrued, however, as limiting the invention to those particularembodiments. Practitioners skilled in the art will recognize numerousother possible embodiments as well as the ones specifically described.For a definition of the complete scope of the invention, the reader isdirected to the appended claims.

This invention describes the combination of a material and itsconfiguration to produce a porous carrier used to temporarily supportsemiconductor device wafers during several manufacturing processes. Theinvention may use a range of materials that exhibit proven compatibilitywith chemicals used in the customer's process. For example, aluminum maybe a common and inexpensive metal of choice, however, aluminum is notcompatible with many alkaline reagents without proper inhibition ofmetal corrosion or is not compatible with halogenated acids.Alternatively, stainless may be a better choice, however, this choice ismore concerned with the type of halogenated acid and concentration.Teflon™ (a trade name for Du Pont's polytetrafluoroethylene resin) maybe a better choice for compatibility, however, the weight of the porouscarrier may become excessive, as Teflon™ has a density of 2.2 g/cm³.Other related materials to Teflon™ perfluoroalkoxy (PFA) and fluorinatedethylene propylene (FEP). Teflon™, PFA, and FEP are all related and arethermoplastics, however, they differ in their melting temperaturesof >300 C, 300 C, and 260 C, respectively. PFA is considered superior tothe others based upon it being used as a coating, such as on aluminum orstainless.

During the processing of a device wafer that is temporarily affixed(bonded) to a sectional porous carrier, it is expected that exposuretemperatures may exceed 250 C, and most probably beyond 300 C. In somecases, it has been requested to expose the temporarily bonded devicesubstrates to 450 C. Where processing needs involve low temperaturepolysilicon (LTPS), material is deposited by vacuum evaporative meansand subsequently must be annealed. LTPS annealing requires temperaturesin excess of 400 C, preferred to 500 C, and most preferred is reachingtemperatures of 600 C. Sectional porous carriers that are meant totemporarily support device wafers must resist such temperatures and doit in a manner that does not result in bending, warping, bowing, orotherwise exhibit deformation in the substrate due to a CTE mis-match.For these temperatures, low CTE value materials are desired by a purematerial with an exhibited CTE value lower than 15 ppm, preferred lessthan 10 ppm, and more preferred less than 5 ppm. Options to purematerials include a mixture of materials and additives that are combinedin a manner to elicit low or non-detectable observed values of bending,warping, bowing, or other deformation. In such cases, the materials usedin such a mixture may exhibit excessive CTE values, however, the mannerthat these materials are arranged and configured shall produce astructure that expresses observed characteristics consistent with thesame structure that is composed of pure materials of a low CTE value. Itshall be assumed that this invention and the varying embodimentsdescribed are not restricted by the methods and processes indicatedhere. One who is familiar with the art shall offer various means oftemporary bonding by a sectional porous carrier using the meansdescribed here, yet varies in sophistication and cost.

Of primary importance for the invention is to produce a sectional porousstructure such that the item exhibits regions or sections of porouscharacter while it performs as a temporary support and facilitates rapiddebonding when exposed to a specific liquid chemistry chosen to affectthe adhesive interface between the device wafer and carrier. The liquidchemistry diffused through the sectional porous areas of the carriersubstrate and operates upon the adhesive at the bondline locationbetween the carrier and device wafer to effect its breakdown andsubsequently release the carrier substrate. The carrier release isremoved by gravity that exposes additional underlying adhesive remainingon the device wafer where it continues to be affected by the liquidchemistry until cleaning is completed. Following cleaning, the devicewafer is rinsed, dried, and becomes ready for the next process step,typically a dicing operation. The porous carrier is sent to a recycleoperation where it is cleaned, tested, and readied for repeating thebonding, processing, and debonding practices on additional devicewafers. The porous carrier may be recycled up to 10× times, preferred upto 20×, and more preferred at greater than 30×. The cost structure forthese options varies with each recycle capacity.

FIG. 1 outlines the invention described as a sectional porous carriershown to contain a sufficient surface uniformity material 1 in variousdesign configurations with a secondary material 2 identified in A, B, C,D, and E. A surface uniform material 1 is needed for interfacial bondingof the device wafer, yet can exist in configurations with material 2varying from a thin laminate of approximately 1% by weight or greater inA, to a complete structure of 100% by weight in B, or a laminate thatcovers the secondary material which may exist at 1% by weight or greaterthat surrounds item 2 seen as an encapsulated structure C. All of thestructures identified in A, B, C, D, and E are considered sectionalporous carriers and exhibit properties sufficient to produce the desiredmain effects. The high surface uniformity and porous material 1 maycomprise a converted mesh, screen, or felt (e.g. non-woven fibermaterial). Examples of simple high surface finish laminate forms of 1that exist in configuration A, include: filter paper, metal felt, andporous coatings. Material 1 may comprise both inorganic and organicmaterials. Material 2 may vary from solid form to a porous material.Examples of solid form materials include glass, silicon, or otherceramic sheets or pieces. Porous forms of material 2 include mesh,screen, and non-woven forms that exhibit a high degree of diffusionpotential.

During the process that utilizes a bonded wafer structure, the inventionporous carrier represented as A, B, C, D, or E is affixed to a devicewafer by adhesive to meet minimum properties desired for grinding andpolishing with subsequent electronics processing. During the debondingstage, liquid chemical penetrates through the sectional porous regionsof the carrier and is brought into direct contact with the adhesive tobreak it down and effect release from the device wafer. In this fashionand when material 2 is a solid form, chemistries enter the porous layer1 described in designs A, B, C, D and E from one of the geometricalsides and processing effects upon the bonded wafer stack. In some cases,the chemistries may enter from all angles to include both horizontal andvertical. When these practices are applied to batch processing wheremultiple device wafer bonded stacks are present in a cassette, theporous carriers allow the liquid chemistry to act upon the bondingadhesive to simultaneously effect release of the carriers.

Various embodiments of the design and construction of the porous carriersubstrate are presented here using different materials. The inventionporous carrier and its use as a temporary support for device wafers andas a release mechanism during batch processing are not limited by theembodiments presented and shall apply to variations not mentioned here.

EXAMPLES

The compositions of the invention and the method of creating theexamples are described. It is understood, however, that the invention isnot meant to be limited to the details described therein. In theexamples, the percentages provided are percent (%) by weight unlessotherwise stated. The invention is further illustrated, withoutlimitation, by the following examples. The measurement of performanceand selectivity of the invention is conducted using practices readilyaccepted by the industry.

To ensure uniformity in thickness and smoothness, all adhesive coatingsare produced on a Brewer Science, Inc. CB-100 spin-coater. Metrologydata is generated by a XP-1 stylus profiler using equipment settings 5mg stylus load, minimum 4 mm distance, and a speed of 0.5 mm/sec. Hotplates are digital controlled systems with aluminum plate protectionfurnace support uses box type #ST-1200C-121216 with microprocessorprogramming, nitrogen purge, and dispersion fan for chamber uniformityThickness is measured using a drop-gauge type, model ID-C112E).Transmittance measurements are conducted with a UV/VIS spectrometer Cary50. Laboratory goniometer set-up uses in-house digital camera,autopipet, and digital protractor with software to support the SessileDrop Technique.

Silicon wafers and glass plates (˜2.5 mm and 0.5 mm thick) are used asan inorganic substrate (carrier substrate) upon which the adhesive isapplied, cured, and subsequent affixing of a porous material is tested.Adhesives used are polyimide, U-Imide C, 35% solids inn,n-dimethylacetamide DMAC (www.unitika.com.jp), a polyethersulfone,Veradel A-301 worked-up into a coating liquid as 35% solids in DMAC.Chemical surface treatments include: fluoroalkyl silane Dynasylan F8815and silicone Dow Corning Q1-4010. Various other chemicals used forporous metal substrate penetration includes isopropanol (IPA),n-methylpyrollidone (NMP), and Isopar G (isoparrafins). Multiple porousmetal samples are used to test and screen surface finish as texturemeasured as Rq. Detailed studies are conducted on other porous metals inthe form of metal felt (non-woven micron-sized wire) as 20BL3 and 40BL3This material forms the basis for the survey, which the invention isdemonstrated.

Example #1

These experiments demonstrate the use of sectional porous metalsubstrates for electronic applications and for rapid debonding.Thickness, transmittance, and texture is measured. Results are reportedin Table 1. A metal woven product, metal screen, (165X1400-304) exhibits<1 um Rq value as texture (surface finish).

TABLE 1 Mechanical properties of several sectional porous metalmaterials. 90 Rq deg. Rq Thick- (10{circumflex over ( )}5 (10{circumflexover ( )}5 ness % T at ang- ang- ID Pattern (mm) 400 nm stroms) stroms)60BL3 Non- 0.13-0.14 6.42 2.41 1.78 woven (felt) AL3 Non- 0.57-0.58 0.673.59 3.21 woven (felt) 60-0075-316 Woven 0.34-0.35 31.80 2.57 5.0580-0037-316 Woven 0.17-0.18 50.53 1.913 4.9 100-0045-304 Woven 0.23-0.2433.57 2.89 3.73 100-0045-316 Woven 0.22-0.23 30.82 3.52 3.46120-0037-304 Woven 0.16-0.17 33.34 3.65 3.13 150-0026-316 Woven0.11-0.12 38.20 1.41 3.04 150-0037-304 Woven 0.10-0.11 39.40 2.94 3.07165 × 1400-304 Woven 0.12-0.13 0.02 0.989 0.802 200-0016-316 Woven0.04-0.06 44.92 2.66 3.08

Example #2

In an effort to demonstrate the dynamic leveling effect of the porouscarrier that occurs during bonding, total thickness variation (TTV) ismeasured on metal non-woven felt before and after bonding to a glasssubstrate. Bonding adhesive includes polyimide that is applied by spincoating to glass, soft baked to 100 C for 5 min, bonding with a <5 psiweight 10 min, and hard baking to 250 C followed by 350 C for 5 min and10 min, respectively. In this case, the metal felt 40BL3 is used forbonding and TTV measurements. The TTV results are shown in Table 2.

TABLE 2 TTV measurements before and after bonding. Results show that TTVreduces with a porous metal carrier by having an avenue of travel andleveling for the adhesive. Glass + Metal Glass Plate Metal Felt 40BL3Felt + Adhesive (um) (um) (um) 2 um 29 um 12 um

Example #3

Efforts to demonstrate a reduction of irregularities of bow and warp dueto CTE mis-matched materials is best conducted with different thicknessof glass (varying modulus). Thick glass exhibits higher modulus vs. thinglass. Higher modulus expresses as a reduced bow and warp during suchdynamic testing. The test will measure the effects of metal non-wovenfelt bonded to glass substrates of different thicknesses (i.e. 0.55 mmand 1.85 mm). The metal felts P/N 20BL3 & 40BL3 (www.porousmetals.com)used for this application have observed similar thicknesses ˜170 um and˜200 um, respectively. A low CTE and crosslinking polyimide is appliedby spin coating to glass, soft baked to 100 C for 5 min, bonded to themetal felt with <5 psi weight 10 min, and hard baked to 250 C and 350 Cfor 5 min and 10 min, respectively. Thickness is ˜10 um. As the bondedsubstrate cools from 350 C to ambient, the metal felt bonded specimensexhibit bow/warp of the glass. The corresponding bow/warp results areshown in Table 3.

TABLE 3 Bow/warp measurements after bonding and cooling from 350 C. toroom temp. Bow/warp of glass + Bow/warp of glass + Glass Plate MetalFelt 20BL3 Metal Felt 40BL3 (mm) (mm) (mm) 0.55 2.5 3.2 1.85 0.7 1.0

Example #4

Wicking tests by chemical diffusion are tested by observing liquidsbeing dropped onto the surface of a porous metal felt (P/N 60BL3,) andobserving if the liquid drop will penetrate into the felt matrix and beobserved, or remain on the surface and not “wet” the surface. A metalporous felt is exposed to specific chemicals that result in a specificsurface treatment to cause a phobic surface to develop. Phobic surfacesare not wetted by philic liquids and when measuring contact angle,treated surfaces will effect greater contact angles. Following surfacetreatment with various chemical agents, the contact angle is measured bygoniometer practices. Surface treatment follows different reagentsapplied to the metal felt and allowed to cure. Subsequent testing ofchemical penetration is conducted with chemicals and observing theirability to “wet” the metal felt.

TABLE 4 Surface treatment, contact angle, and chemical wetting of metalfelt (60BL3). Treatment Contact Angle DIW IPA NMP Isopar G Silicone101.02 No slow No Yes F 8815 107.87 No No No No None 60.6 No Yes Yes Yes

What is claimed is:
 1. A sectional non-perforated porous carriercomprising a total of two parts, a silicone or fluoro siloxane surfacetreated metal nonwoven felt wherein the treated nonwoven felt exhibits acontact angle from water as measured by the Sessile Drop Technique ofgreater than 90 degrees and a solid ceramic section having one or moreliquid impervious geometric sides and sufficient surface uniformityhaving total thickness variation less than 10 microns to accept a devicesubstrate with applied adhesive that is impervious to liquid processchemicals whereby a temporary support is formed that exhibits handlingability and resistance to process chemicals necessary for manufacturingsteps and is later subjected to selective rapid diffusion of liquids todirectionally penetrate and contact adhered regions causing release ofthe carrier without harm to the corresponding device substrate andwherein the nonwoven felt further comprises a polymer binder.
 2. Thesectional porous carrier of claim 1, wherein the solid ceramic sectionis a ceramic selected from the group consisting of silicon, quartz,glass, and sapphire.
 3. The sectional porous carrier of claim 1, whereinthe binder is a polymer selected from the group consisting of polyimide,polyamide, polyamideimide, polybenzimidazole, polybenzoxazole,polysulfone, polyethersulfone, polyphenylsulfone, polyarylether,polyetheretherketone, polyvinyidenedifluoride, cyclic olefin copolymer,polyethylene terphthalate, polybutylene terephthalate,polyacrylonitrile, polyaryletherketone, polyketoneketone,styrene-acrylonitrile, polycarbonate, polystyrene, polyvinylchloride,polyphenylene sulfide, polytrimethylene terephthalate, polyvinylidenechloride, acrylonitrile butadiene styrene, liquid crystal polymer,silicone, and epoxy.
 4. The sectional porous carrier of claim 1 whereinthe binder is an inorganic salt selected from the group consisting ofsilicates of sodium, potassium, lithium, aluminum, magnesium andcalcium.
 5. The sectional non-perforated porous carrier of claim 1wherein the measurement of surface uniformity as total thicknessvariation is to be less than 5 microns.
 6. The sectional non-perforatedporous carrier of claim 1 wherein the measurement of surface uniformityas total thickness variation is to be less than 1 micron.
 7. Thesectional porous carrier of claim 1, wherein the treated nonwoven feltexhibits a contact angle for water as measured by the Sessile DropTechnique is greater than 100 degrees.
 8. The sectional porous carrierof claim 1, wherein the treated nonwoven felt exhibits a contact anglefor water as measured by the Sessile Drop Technique is greater than 110degrees.